This book presents a factual analysis of the history of population policy, especially the fertility policy, mainly the reproduction of the policy since the founding of New China, especially the promotion of one child per couple, including the background of the policy's introduction, the formulation of the decision, the prediction of possible problems, and the choice of decision to deal with them. It summarises the basic experience of China and the international community in implementing population policies, and proposes to follow the path of family planning with Chinese characteristics and implement population policies that are compatible with it.